SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f18d464541fb38d9816ce5e3e6f0348e62e03663f08a11cda53f5a7232d0473' 
  AND token = 'c2XkXKdYH5/pmOAodwydwBbNbX30TwMAs2jjCjGc4jo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}